1. Field of the Invention
The present invention relates to a photosensitive material processing apparatus for drying a photosensitive material processed with processing solutions by a heat roller system.
2. Description of the Related Art
Conventionally, a photosensitive material is sequentially processed with processing solutions which are a developing solution, a fixing solution, and cleaning water and then dried by for example an automatic developing apparatus. In conventional drying process, warm air is blown onto a photosensitive material which has been treated with cleaning water so as to dry the photosensitive material.
However, with this method, when a large amount of photosensitive material is processed, the drying temperature of the drying process section is adversely affected. In addition, the thermal efficiency in the drying process is insufficient. On the other hand, with electronic advancements in recent years, the need for quick processing of photosensitive materials such as graphic art photosensitive material, scanner photosensitive material, and X-ray photosensitive material is becoming greater.
To quickly process such photosensitive materials, a photosensitive material processing apparatus having a drying process section using a heat roller system has been proposed as disclosed in Japanese Patent Application Laid-Open No. 4-155334. With reference to FIG. 19, an example of such an apparatus will be described in brief.
FIG. 19 is a partial sectional view showing a drying process section 300 of a photosensitive material processing apparatus of the type mentioned above. In the drying process section 300, a pair of a heat roller 310 and a press roller 312 are disposed. The rollers 310 and 312 nip and convey a film F from which most of the excessive water has been removed by a squeeze roller (not shown) in the preceding step. The heat roller 310 is provided with a cylindrical roller body 314. The roller body 314 is rotated in the direction of an arrow denoted by G by a motor (not shown). At an axial core portion of the roller body 314, a heating halogen lamp 316 is disposed for heating the roller body 314.
The press roller 312 is rotatably supported to the apparatus body by a bearing (not shown). The outer circumference of the press roller 312 is composed of an elastic substance 312A such as rubber. A portion of the press roller 312 presses against the circumferential surface of the heat roller 310. Therefore, the film F is nipped by a predetermined nipping pressure and conveyed by the heat roller 310 and the press roller 312 in the direction of arrow A shown in FIG. 19.
In the nipping and conveying step, water on the surface of the film F is squeezed off and then dried by heat from the heat roller 310. In the heat roller system, since the film F contacts the heat roller 310, the film F is directly heated by heat transferred therefrom. Thus, the thermal efficiency of this system is relatively high and the film F can be completely dried.
However, in the above-described heat roller system, water 320 which contains processing solutions and which adheres to the film F is squeezed off by the heat roller 310 and the press roller 312. The squeezed off water 320 is trapped in a triangle-shaped groove portion 318 defined by the heat roller 310 and the press roller 312.
After the film F has passed between the heat roller 310 and the press roller 312, there are cases when a certain amount of a time lapses until the next film F passes therethrough or the apparatus is stopped after the completion of the process. In such cases, the water 320 which is trapped in the groove portion 318 is evaporated by the heat of the heat roller 310. Thus, water-soluble polymers, sensitizing dye, calcium, and so forth which are dissolved in the water 312 are deposited in striped patterns on the surface of the press roller 312.
Thus, after the process is resumed, when the next film F contacts the heat roller 310 and the press roller 312, substances such as water-soluble polymers, sensitizing dye, and calcium deposited on the surface of the heat roller 310 and the press roller 312 are conveyed to the film F. Therefore, the deposited substances will contaminate the surface of the film F, thereby detracting from the image quality thereof.